Slave Node Timing Redistribution via Peer Holdover

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Solution Overview

Problem

In packet switched networks, Slave nodes with inferior oscillators face limited holdover time, leading to degraded synchronization performance and potential call drops when communication with the Master node is lost or degraded due to jitter and latency, with no proactive mechanism for redistribution of timing and synchronization.

Innovation Solution

Slave nodes maintain a peer list of nodes sharing the same Master node and announce their holdover time, allowing them to temporarily take on a mini-Master role when communication is lost or degraded, enabling dynamic redistribution of timing and synchronization among peers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If Slave nodes use inferior oscillators to reduce cost, then device complexity and cost are reduced, but holdover time is limited and synchronization performance degrades

Engineering Contradiction:
ImprovecostVSAvoidsynchronization performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces an intermediary mechanism where peer Slave nodes act as temporary timing sources for each other. When a Slave node experiences communication degradation with the Master node, it can announce its holdover time to peer Slave nodes, which then use this peer as a timing reference instead of relying solely on their own inferior oscillators. This peer-to-peer timing redistribution extends the effective holdover time and maintains synchronization performance without requiring expensive oscillators in each node.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If Slave nodes rely on Master node for synchronization, then synchronization accuracy is maintained, but network stability degrades when communication is lost or degraded due to jitter and latency

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidnetwork stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent implements preliminary action by having Slave nodes proactively announce their holdover time capabilities to peer Slave nodes before communication failure occurs. This advance notification allows peer nodes to prepare alternative timing sources, so when the Master node communication is lost or degraded, the transition to peer-based timing redistribution happens seamlessly without disrupting network stability. The peer list and holdover time announcements are maintained in advance, enabling rapid response to communication failures.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If Slave nodes maintain simple master-slave hierarchy, then device complexity is reduced, but adaptability decreases when dynamic redistribution of timing is needed

Engineering Contradiction:
Improveprotocol complexityVSAvoiddynamic redistribution capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by enabling the timing hierarchy to dynamically reconfigure based on network conditions. Slave nodes continuously monitor communication quality with the Master node and can dynamically transition from a static master-slave hierarchy to a dynamic peer-to-peer timing redistribution mode. When communication degradation is detected, Slave nodes dynamically announce their holdover time and establish temporary timing relationships with peers, allowing the network to adapt to changing conditions while maintaining relatively simple protocol operations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3140933B1System and method to dynamically redistribute timing and synchronization in a packet switched network
Publication Date: 2020.10.28 NOKIA SOLUTIONS & NETWORKS OY
  • EP3140933B1 patent drawingFigure 1
  • EP3140933B1 patent drawingFigure 2
  • EP3140933B1 patent drawingFigure 3

AI summary

Systems, methods, apparatuses, and computer program products for dynamically redistributing timing and synchronization in a packet switched network are provided. One method includes creating, by a slave node, a peer list comprising an identifier of at least one peer slave node that shares a same master node as the slave node or that has a certain predefined affinity with the slave node. The method may also include announcing a holdover time of the slave node to the at least one peer slave node, and, when a predefined event occurs, announcing to the at least one peer slave node that the slave node is taking on a mini-master role for at least the announced holdover time.